Process for the operation of the vaporizers of air resolution plants



Aug. 14, 1934. M, FRANKL 1,970,300

PROCESS FOR THE OPERATION OF THE VAPORIZERS OF AIR RESOLUTION PLANTS Filed Oct. 14. 1951 INVENTOR- AT ORNEYS v Patented Aug. 14, 1934 UNITED STATES PATENT OFFICE PROCESS FOR THE OPERATION OF THE VAPORIZERS OF AIR RESOLUTION PLANTS Application October 14, 1931, Serial No. 568,713 In Germany January 13, 1931 4 Claims- (Cl. 62-1755) i The invention relates to a process and to an apparatus for the operation of vaporizers for the resolution of gaseous mixtures; More particularly it relates to the resolution of air into nitrogen and oxygen and includes correlated improvements and discoveries whereby the resolution of gaseous mixtures is enhanced.

As is known, the resolution of air takes place in the manner that it is first liquefied and that the nitrogen is separated, completely or partially, as

may be required, from the liquefied air by rectification, whereupon a liquid, rich in oxygen flows down into a vaporizer wherein it vaporizes with attending liquefaction of air, and is drawn off in gaseous form.

The air to be liquefied must, however, be compressed to a pressure of from 2.5 to 5 atmospheres absolute, according to whether a more or a less pure oxygen is to bdrecovered, because the oxygen vaporizes at a higher temperature than that at which uncompressed air would liquefy. The compression makes it possible for the liquefaction to take place above the vaporization temperature of the oxygen.

The recovery of oxygen with a content of 40 to 50 per cent of oxygen is, in cases where this is suitable, more favorable economically and technically than that of pure oxygen because, for it, the air need be compressed only to 2.5 to 3 atmospheres absolute. However, this procedure entails a certain disadvantage. If, for example, the vaporizer is charged with a liquid having an oxygen content of per cent, then since the nitrogen vaporizes first, the liquid thereby becomes richer 35 in oxygen. The 45 per cent oxygen liquid which constantly flows in has a lower specific gravity and therefore ascends by the shortest path, while the heavier liquid, richer in oxygen, collects at the bottom of the vaporizer and can be vaporized only with compressed air of greater pressure than would be necessary for a uniform mixture having an oxygen content of 45 per cent.

It is an object of the invention to provide a 5 process in which the disadvantage above mentioned is obviated by effecting an intimate admixture of the heavier and lighter liquids.

It is a further object of the invention to provide a process for the operation of vaporizers for the resolution of air into oxygen and nitrogen whereby a liquid poor in oxygen and a liquid rich in oxygen are intimately admixed in a vaporizer by occasioning an artificial circulation.

Another object of the invention is to provide a vaporizer of suitable construction wherein an intimate admixture of liquids of different specific gravities may be effected.

, Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and the apparatus embodying features of construction, combinations of elements and arrangement of parts which are adapted to effect such steps all as exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

For a fuller understanding of the nature and objects of the invention reference should be had to the following detailed description taken in connection with the accompanying drawing, in which:

The single figure depicts a circulation in a vaporizer with an upright pipe bundle in which 5 the circulation is effected by means of an injector operated with compressed gaseous mixture as a medium.

In the practice of the invention in a procedure to effect the resolution of air a more uniform composition of the vaporizing liquid is brought about by constant and intimate admixture of the vaporizer liquid richer in oxygen with the inflowing liquid poorer in oxygen, thereby obviating a necessarily higher compression of the air to be 95 liquefied.

The following description presents an illustrative embodiment of a manner in which the aforesaid admixing may be effected.

A simple way consists in bringing about by ascending vapor bubbles an automatic and extensive circulation of the contents in a vaporizer 1 on the principle of the functioningof a Mamut i. e., an air lift pump. For this purpose the vaporizer is provided with pipes a which may be in the form of a vertically disposed bundle.

The pipes a are enclosed in an outer jacket 1 which is provided with an inlet 11 for the compressed gaseous mixture, as air, an outlet 9 for withdrawal of the liquefied gaseous mixture, and 0 an outlet 10 for removal of the vapors produced about the pipes. Communicating with the lower part of the vaporizing space and with the compressed gas inlet 11 is an injector 1 which is in connection also with the upper part of the vaporizing space by means of a conduit 12. The intimate admixing of liquid poor in a higher boiling constituent with a liquid richer in such constituent is effected by bringing about a circulation of the liquid by action of the injector as shown in the drawing. Inoperation, liquid is continuously Withdrawn from the vaporizer below and is again conveyed above into the vaporizer by means of the pipe 12, and the compressed air nozzle 1. The compressed air may be taken from the pipe 11 on the condenser side of the vaporizer. The vaporized oxygen is Withdrawn through the outlet 10 and the liquefied air through the outlet 9.

The procedure herein described for the operation of Vaporizers, particularly those used for the resolution of air into nitrogen and oxygen, may advantageously be utilized for the recovery of a 40 to 50 per cent oxygen. This is accomplished by admixing the vaporizer liquid richer in oxygen with the inflowing liquid poor in oxygen in a manner to effect an intimate distribution by an artificial circulation. The production of a liquid containing 40 to 50 per cent oxygen is thereby effected in an economical and efficient manner.

Since certain changes in carrying out the above process and in the constructions set forth, which embody the invention may be made without departing from its scope, it is intended that all matter contained in the above description or shown in the accompanying drawing shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all of the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, might be said to fall therebetween.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. A process for the operation of Vaporizers for the resolution of gaseous mixtures, which comprises introducing a liquid poor in a higher boiling constituent into a vaporizer containing a liquid richer in said constituent, and effecting an intimate admixture of said liquids by artificial circulation occasioned by withdrawing a portion of the liquid rich in the higher boilling constituent from the base of the vaporizer and conducting it for admixture to the top thereof.

2. A process for the operation of Vaporizers for the resolution of air which comprises introducing a liquid poor in oxygen into a vaporizer containing a liquid richer in oxygen and effecting uniform admixture of said liquids by artificial circulation occasioned by withdrawing a portion of the liquid rich in oxygen from the base of the vaporizer and conducting it for admixture to the top thereof.

3. A process for the operation of Vaporizers for the resolution of air which comprises introducing a liquid poor in oxygen into a vaporizer containing a liquid richer in oxygen and eifecting uniform admixture of said liquids by artificial circulation occasioned by withdrawing a portion of the liquid rich in oxygen from the base of the vaporizer and conducting it for admixture to the top thereof by means of compressed air.

4. A vaporizer for the resolution of gaseous mixtures comprising in combination an outer jacket provided with inlet and outlet means, a plurality of vertical tubes positioned within said jacket and an injector positioned without said jacket for withdrawing liquid from near one end of said tubes and introducing it near the other end of said tubes.

MATHIAS 

